Firstly, the wavelength of 1270nm, 1290nm, 1310nm and 1330nm in the four channels of the optical terminal was converted into 100G CWDM4 service for transmission through OTU.

Due to the long distance transmission (10km), the optical signal loss is large, and the SOA optical amplifier is used at the receiver to enhance the transmission power of the signal in advance.

In this scheme, a fiber attenuator is needed to adjust the optical power of the transceiver at the receiving end to avoid excessive optical power damage to the transceiver.